Piston.



ii sas .anivnic.

DAVID r. CRAWFORD, or PITTSBURGH, PENNSYLVANIA.

PISTON.

T0 all whom t may concern:

Be it knownthat l, DAviD F. CRAWFORD, a citizen of the United States,residing at Pittsburgh, vin the county of Allegheny and State ofPennsylvania, have invented certainnew and useful Improvements inPistons, of which the following is a specification.

The invention relates to pistons and more particularly to that class ofpistons used in steam llocomotive cylinders, and has for its principalobjects the provision of a piston having the properties of uniformexpansion and contraction without increasing thetendency to'weai` thecylinder; the provision of a steam locomotive piston that requires notail rod for the preventioiifof gouging the cylinder walls; theprovision of a ooi'nposite piston wherein the parts combining to make upthe piston 'may be inexpensively made and readily assembled and takenapart; the provision of a piston wherein the wearing yface may' bereplaced' when worn without necessitating the waste incident to thediscarding of a whole piston and the expense incident to refitting a newpistonupon the piston rod; aiidfsuch other improvements as willhereinafter appear. One embodiment of the invention together withmodiiications of certain details of construction are shown in theaccompanying drawings, whereinv Figure lis a longitudinal sectionthrough the piston and a portion of the cylinder; Fig. 2 is an elevationof a locking ring used in the piston shown in Fig. 1; Fig. 3 is alongitudinal section of a portion of a piston showing a modified form ofring locking mechanism; Fig. 4 is a front elevation of a portion of thedevice shown in Fig. 3; and Figs. 5, 6, v7, 8 and '9 are longitudinalsections of a portion of a piston showing' modi.- fied vforms of ringretaining devices.

Referring to Fig. 1, the piston consists of a central body portion 1formed of steel by a' rolling process, the body portion Vconsisting ofa. hub portion 2 and a cylindrical face por- `tion `3. A piston rod 4extends through the hub 2 and is secured thereto by means of the nut 5.

It has been found that where 'a piston made Jof harder material .thanthe cylinder wall isl used in locomotive service', it was necessary toprovide. a tail rod which had a bearing in the front end of the cylinderand projected therethrough. Without the use of such tail rodthe cylinderwall was found to: be gouged and scoredby the piston due `Specicatioiiof Letters Patent.

Patenten oct. 2e, isis.

Application flied January 9, 1915. seriai No. 1,313;

to the greater hardness of the piston and to prevent such scoring of thepiston a wearing lln der is made. A l

It has been found thatv pistons made by a Arolling process are farsuperior to those der 9. The 'ringv6 is adapted to be slidonto thecylindricall face portion 3 of rthe center portion 1, and is retained bymeans of the forcing the locking ring 11 from thefgroove 6 is providedpreferably made from similar material to thatof which the cylin-v yflange'lO and a split locking ring 11, Figs. 1V

and then sliding the wearing riiig6 from the face portion 3. y 1

The wearing ring 6 may be retained in a number of ways, some of whichare dis closed in Figs. 3 to 9 inclusive. xR-eferring `V to Figs. 3 and4, the ring 6 is retained by means of the flange 10 and a sectional ring11 mounted in the groove 12. The ends of the'ring sections 11 aresecured to thefcyliiidrical portion 3 by means of the bolts 13 whichextend through holes in the ring sec- -tioiis 11 and the cylindricalportion 3. -The ring sections 11 engage the wearing ringo ina mannersimilar to the construction of Fig. 1.

1 Fig 5 discloses' acylindrical portion 3 of the piston, having thereonthe wearing ring 6 retained by'ineans of a flange A10a and a flat ring14 which is secured by studs 15 tothe-cylindrical facel portion 3a. The`ring 14 is slipped'over the studs 15 and abuts the wearing ring 6. Thenuts 16 are screwed tight against the ring 14 and thereby secure thering 14 firmly against the wearing ring 6.

Fig. 6 shows a wearing ring 61D mounted upon a cylindrical face portion3b which is provided with a flange 10b. The wearing ring 6b is securedto the cylindriealface por? tion 3b by means of bolts 17, one of whichis disclosed, which extend through the flange 10b and screw intothewearing ring. Longitudinal movement of thewearing ring is preventedin one direction by the flange 10" and inthe opposite direction by thebolts 17.

Fig. 7 shows another modified form,

wherein the wearing ring G is mounted upona c vlindrical face portion 3cwhich is provided with a flange 10C for holding the wearing ring againstmovement in one direction. Movement in the opposite direction isprevented by-means of a plurality of arcuate keys 18, one of which isdisclosed, having enlarged inside edges 19 which are adapted to beinserted .in a series of undercut grooves 20.

In the construction shown in Fig. 8, the lwearing,ring'G is retainedupon the cylindrical face portion 3d by means of' the flange 10d and aseries yof machine screws 21, one` of which is shown, the screwsextending through the face of the wearing ring 6l into the cylindricalface portion 3d.V The heads of the machine screws 21 are located incounter sunk holes 22 so that they are beneath the face of the wearingring.

Another modied form of construction is shown in Fig. 9 wherein a pair ofWearing rings 22, each carrying a packing rm'g 23,V

are arranged on each side of a central flange 21 which is integral withthe cylindrical vface portion 3e. Rivets 25, one of which is shown,extends through both of the wearing rings 22 and the flange 24, which.face andprovided With an annular flange,

a ring adapted to be slid longitudinally on the cylindrical face of thebody portion and abut the flange, a peripheral groove in thecylindrical, face of the body portion and a detachable lock ring in thegroove adapted to engage the end of the first ring to sei cure it to thebody ortion.

2. A composite cylinder piston comprising a central body portion havinga cylindrical face and provided with an annular flange, a ring adaptedto be slid longitudinally on the cylindrical face of the body portionand abut* the flange, a peripheral groove in the cylindrical face of thebody portion, a locking member in the groove adaptedA Ato engage the endof the ring to secure it to the body portion andv means for retainingthe locking member in the groove.

vIn testimony whereof I have hereunto signed my name in the presence ofthe two subscribed witnesses.

DAVID F. CRA'WFORD. Witnesses: l

Ro'r. REILLY,

IV. S. CAREY.

